I know we're all just throwing stuff at a wall right now, but I am increasingly hopeful that Canon will actually surprise us and break the mold a bit here.
I mean, the market for 1-series users remains for... the 1-series. The CF Express + SD card slots speak to a more consumer philosophy along the lines of the EOS R5. The eye control and flip screen speak to a more consumer philosophy. The removal of the lower rear LCD and removal of WFT accessory point(no backwards compatibility for those who already dropped $600 on one) speak to more of a consumer philosophy.
If Canon has always continued the 1-series to be exactly what it's always been since the beginning of time, why would they turn the 1-series into a 3-series?As some others have said, if this camera "bridges" the R5 and 1-series, I still bet that it will match or exceed the resolution of the R5.
I mean, what kinds of consumers buy the 1-series? Historically, you see it being sports and wildlife consumers, who would both appreciate additional reach, since this is the market that also often ends up buying the 7D, which was always formerly considered to be a consumer's 1D. If Canon makes the R3 about 50 megapixels, the 1.6x crop mode will be very close to the 7D Mark II resolution, which would be a huge boost for this camera towards that market.
If the 1-series R1 turns out to suddenly be high-resolution with tons of untested cutting edge tech, you could lose a lot of the routine "pay whatever it takes" 1-series buyers who know what they can expect and can trust their cameras, while appealing more towards consumers who are worried about resolution, who will ultimately buy the R5 or the R3 because it costs less.
I know AP photographers who are routinely infuriated by their A9s and use their old 1-series cameras. Those are the commercial customers who both have a limitless budget for the 1-series and do not want to be blindsided by tech the way the AP and Sony forced them into.